Stirring the pot... Mechanical vs. Hydraulic clutch?

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Chained_360

Chained_360

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In my quest for gear-hammering fun, I've encountered an issue that I need some external help with. I'm in the process of collecting parts to swap my '68 Notchback Barracuda (mild 360/904) from automatic to manual, and I don't know what to do about the clutch.

Here's the deal; During the summer, my Barracuda is my daily driver. I love cruising around in it, but I'm not hesitant to stretch its legs. I'm swapping an A833OD for my 904 because I want this thing to get decent gas mileage and be well behaved on the highway. That being said, I still will probably go to the drag strip for fun from time to time, and maybe toy around with people at stoplights.

So, what do I do for a clutch? I've never owned a car with a mechanical clutch, though I drove one once at work (old farm truck, not a hot rod). My winter daily driver ('90 F350) has a hydraulic clutch, and it seems to do fine except for when it gets cold, which just makes the clutch stiff and slow to react until everything's up to temperature. It seems like a brand new reproduction mechanical clutch setup can be had for $200-250 from classic industries. Conversely, I know I can fabricate my own hydraulic clutch setup for around $150-200. I'm not running a crazy pressure clutch, just an O'Reilly's "heavy duty" OEM replacement clutch.

The biggest influences on my decision are:
- I have Hooker long-tube headers. I've heard they fit a stock clutch setup, but I'm not 100% sure
- Cost -- I'm a cheap bastard.
- Reliability -- I don't mind adjusting a clutch from time to time, but I do want a clutch that will shift smoothly every time without binding or hesitation, and most importantly will not break for no reason
- Feel -- I don't want a mushy pedal, but I'm not looking for a leg workout either. Just something that tells me what is going on inside the bellhousing.

I know this thread has been done before, but it's usually within the context of T56 or TKO swaps. I'm interested in how this all applies to OEM Mopar trannies.
 
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If I had the working knowledge, material & talent to a Hyd. Clutch, I’d do it.
 
The mechanical set up is likely going to be your cheapest, and easiest, option with a A833OD. If you don't have some crazy aftermarket clutch designed for high horsepower the leg effort won't be bad, and you can just buy all of your parts. If you can scare up some of them used even better.

The hydraulic set up will likely cost more. It's not any harder to set up really, it's just like a brake system with a master cylinder and slave. Just size them right and bleed it and you're good to go. But because the throwout bearing/slave set up is likely going to be aftermarket, it's going to cost more. The stuff made to fit the 833's "off the shelf" is well over $600 from McLeod or American Powertrain. Heck the McLeod throw out is like $370 by itself. Which is nuts. I'm positive there are cheaper ways to do it, but then you're custom building your own set up. Which may be cheaper, but will be labor/time intensive.

By comparison, the T56 hydraulic clutch set up is easy. You can buy a hydraulic throwout bearing for a Viper and bolt it right on for $100, at which point you just need a clutch master and lines.

Right now my Duster has a mechanical set up for the 833 that's in it, and it works fine. When the T56 goes in it will go hydraulic. Not because I think either one is particularly better, they both have pro's and cons, but because its not worth it in either case to convert a transmission to use something other than what it was designed for. Either way you get into custom or aftermarket parts to do a conversion, and it can get pricey. I wouldn't put a hydraulic set up on an A833, and I wouldn't make a mechanical set up for a T56. Just my opinion of course.
 
I'm not fond of hydraulic clutch activation. Never really cared for the cable stuff either. Always felt mushy to me.

The mechanical linkage is so simple. It's already engineered. Almost a no brainier.

Pedal effort is 98% plate load and 2% in the linkage.
 
yellow rose said:
I'm not fond of hydraulic clutch activation. Never really cared for the cable stuff either. Always felt mushy to me.

The mechanical linkage is so simple. It's already engineered. Almost a no brainier.

Pedal effort is 98% plate load and 2% in the linkage.
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So I'm sure you would recommend a nice soft diaphragm clutch! LOL
 
yellow rose said:
I'm not fond of hydraulic clutch activation. Never really cared for the cable stuff either. Always felt mushy to me.

The mechanical linkage is so simple. It's already engineered. Almost a no brainier.

Pedal effort is 98% plate load and 2% in the linkage.
Click to expand...

I'm with you on this one.
Especially since it's going to be running in a cold climate.
 
72bluNblu said:
I wouldn't put a hydraulic set up on an A833, and I wouldn't make a mechanical set up for a T56. Just my opinion of course.
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yellow rose said:
I'm not fond of hydraulic clutch activation. Never really cared for the cable stuff either. Always felt mushy to me.

The mechanical linkage is so simple. It's already engineered. Almost a no brainier.
Click to expand...
That makes sense. OE is OE, that's a very good point. Another thing going for mechanical is that in my mind it has somewhat of a cool factor, everything nowadays is hydraulic or cable.
 
Mechanical is the way to go, the pros of hyd don't outweigh the potential problems.
 
rumblefish360 said:
Nope! That’s the Ferds job.
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True. The 'Cuda usually doesn't see action between November and mid April.
What's strange is that my 1-ton loves the cold. For some reason it runs the best between 20-40 degrees above zero. Below that, it'll still crank and fire right away, but anything with hydraulic or transmission fluid in it is stiffer than a board until it warms up.
 
Just shift your 904 one gear at a time. When you get tired? Leave it in drive. Best of both worlds. :poke:
 
72Dart6pack said:
Just shift your 904 one gear at a time. When you get tired? Leave it in drive. Best of both worlds. :poke:
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That's what I'm doing for now, but I've yet to drive a fast car with a stick. My brother's Subaru Outback has a 5-speed, but man is that thing gutless compared to the Cuda. I do have a 460 with some get-up in my F350, but it doesn't like being shifted like a race car.

I thoroughly enjoy driving manual transmissions, but I will admit that the 904 currently installed is the funnest automatic I've driven.

Having a third pedal in the car will also act as a thief/sibling/"friend" repellent.
 
Just an opinion, but for what your doing, go with the stock mechanical linkage. Do yourself a favor and reinforce the fender apron where the outside pivot stud goes and consider a torque strap on the engine. The stock linkage can have issues and bind if the engine moves around too much. If you put a diaphragm clutch plate in there, don't install the over-center spring.
 
get a manual pedal setup and rig the clutch pedal to push the 904's kickdown lever. That would be fun to push the "clutch" and have your car drop a gear for instant compression brake or burnout.

Buddy had a Mcleod hydro setup on his 340 64 Barracuda, Lakewood bell, 833: initial firewall flex (fixed with trans support bar to shock mount) , constant adjusting the hydro throw out (had the bleeder come down from the botton, how do you bleed it like that or did he install it upside down?) and the feel was mush. No feedback. I didnt like it.
 
I like my Diaphragm clutch and mechanical linkage. Adjustments are few.
I did not like the od box; Second sucked until I installed 4.10s. But then first sucked worse. Third was direct and with 4.10s wasn't too bad. 4.30s were better.I found the splits were just too far apart for a high-reving engine. I had a hi-Compression 360 with a 223* cam at that time.

If your cam is 230* or more, then a regular box would be my choice. Since you have a 360, they will pull 3.55s ok with a clutch.The clutched-360 will also pull 3.23s but then the 3.09 low gear SET from a 65 Barracuda puts the snap back into first gear. I converted mine to a longtail,and put the shifter between the buckets; one of my better ideas.
The nice thing about the 8.75 is that you can have several chunks set up and ready to go. A swap-over is only about 1.5 hours on your back in the driveway. A lot less on a hoist.
 
pishta said:
Buddy had a Mcleod hydro setup on his 340 64 Barracuda, Lakewood bell, 833: initial firewall flex (fixed with trans support bar to shock mount) , constant adjusting the hydro throw out (had the bleeder come down from the botton, how do you bleed it like that or did he install it upside down?) and the feel was mush. No feedback. I didnt like it.
Click to expand...

That’s the problem with adapting a hydraulic set up onto a transmission that didn’t have one. The hydraulic throw outs in the Mcleod and American Powertrain kits are not specifically for 833’s, they’re mass produced throw outs with adapters. So, you get some issues, like bleeders in inconvenient places. There’s a procedure for it of course but it makes things harder.

As for the feel, that can be adjusted same as a brake system. Changing the bore on the master cylinder can reduce the amount of advantage. Changes the stroke and the pedal effort, just like changing from a 1-1/32” brake master to a 15/16”.
 
AJ/FormS said:
I like my Diaphragm clutch and mechanical linkage. Adjustments are few.
I did not like the od box; Second sucked until I installed 4.10s. But then first sucked worse. Third was direct and with 4.10s wasn't too bad. 4.30s were better.I found the splits were just too far apart for a high-reving engine. I had a hi-Compression 360 with a 223* cam at that time.

If your cam is 230* or more, then a regular box would be my choice. Since you have a 360, they will pull 3.55s ok with a clutch.The clutched-360 will also pull 3.23s but then the 3.09 low gear SET from a 65 Barracuda puts the snap back into first gear. I converted mine to a longtail,and put the shifter between the buckets; one of my better ideas.
The nice thing about the 8.75 is that you can have several chunks set up and ready to go. A swap-over is only about 1.5 hours on your back in the driveway. A lot less on a hoist.
Click to expand...

I don't know what cam I have in the motor as the previous owner installed it. I know it's nothing crazy though, it has a very smooth idle. I have 3.23s in the rear. I'm aware of the wide ratios, but I really want that OD gear. I already have the box, so I can live with a low 2nd gear
 
Chained_360 said:
I don't know what cam I have in the motor as the previous owner installed it. I know it's nothing crazy though, it has a very smooth idle. I have 3.23s in the rear. I'm aware of the wide ratios, but I really want that OD gear. I already have the box, so I can live with a low 2nd gear
Click to expand...

So did I; want the od. So much so, that I traded a 2.47 close ratio for it. Straight up.
I broke three of those od boxes and gave up. I blew up two of the weak-azz od gears, and stripped all the teeth off the input/cluster drive off a third. I got a bigger cam and retimed it to get rid of some bottom-end torque. Then I stuck a GVOD on the back, and tried 4.30s. Problem solved for one summer.Just so you know; (3.23 x 1.67)/1.92 is like running a 2.81 rear gear with a regular box..

I wish you better luck.
 
In my race car I run a hydraulicly activated mechanical clutch. Love it.
 
Not quite there yet on my build .. but considering hyd clutch .. due to hearing QuickTime bellhousing fitment issues with factory forks .. and also flexing ?...
 
rrvolare said:
Not quite there yet on my build .. but considering hyd clutch .. due to hearing QuickTime bellhousing fitment issues with factory forks .. and also flexing ?...
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If you run a non-diaphragm PP, with a high clamp load (like a 3800 say) You have to put a pretty good amount of leg power into disengaging the clutch. This leads to the firewall flexing, so IIRC the factory provided a little strut to redirect some of that force into the frame. That flexing translates to a reduced amount of plate departure, and so you had to run the freeplay on the small side. And that led to more frequent adjustments.
My smallblocks have never needed that strut. And the CenterForce I now have, is a nice Granny-friendly clutch, yet it chirps the tires into third at over 80mph
 
j par said:
In my defense the title mentioned stirring the pot! LOL
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And nobody stirs the pot like you. LOL. My opinion is to stick with manual linkage. It will never leak. Plus, it is about as basic and simple as you will get.
 
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